The present invention relates to a method and system for determining a vehicle driving environment, and more particularly, to a method and system for determining a vehicle driving environment that adapts to an undulating road.
Current systems for detecting approaching objects, such as a vehicle or a signpost, generally project a radar beam and analyze the reflected wave. To cover more area, such radar beams are scanned horizontally. Generally, where the scanning angle is varied, it is varied in a horizontal direction.
But the road a vehicle follows is rarely flat. In situations where the road has undulations, as shown in FIG. 1, a vehicle 10 often cannot detect an approaching object 11 using current systems. And when the vehicle 10 is driven in a mountainous district, not detecting an approaching object 11 becomes more problematic.
An exemplary driving environment determining method for a vehicle according to a preferred embodiment of the present invention includes: scanning a radar beam from the vehicle at a variable vertical angle; detecting a reflective wave of the radar beam reflected from an object; detecting the vertical angle of the radar beam when the reflective wave is detected; calculating a relative speed of the preceding object based on the reflective wave; detecting a vehicle speed of the vehicle; calculating an absolute speed of the object based on the relative speed and the vehicle speed; comparing the vertical angle with a predetermined angle; and comparing the absolute speed with a predetermined speed.
The absolute speed of the preceding object may preferably be calculated as a sum of the relative speed and the vehicle speed, and the predetermined angle and the predetermined speed are preferably preset to zero (0).
In the case that the vertical angle is above the predetermined angle and the absolute speed is different from the predetermined speed, the method concludes that either an incline is in front of the vehicle or that the object is large.
In the case that the vertical angle is greater than the predetermined angle and the absolute speed is equal to the predetermined speed, the method concludes that the object is stationary.
In the case that the vertical angle is less than the predetermined angle and the absolute speed is different from the predetermined speed, the method concludes that a decline is in front of the vehicle.
An exemplary driving environment determining system for a vehicle according to a preferred embodiment of the invention includes: a radar for scanning a radar beam and detecting a reflective wave reflected from an object; a mirror for adjusting a vertical angle of the scanned radar beam according to an angular position thereof; a mirror angle detector for detecting the angular position of the mirror; a stepper motor for adjusting the angular position of the mirror; and an electronic control unit, where the electronic control unit executes programmed steps for: calculating a relative speed of the object based on the reflective wave detected at the radar; calculating an absolute speed of the preceding vehicle based on the relative speed and a vehicle speed of the vehicle; detecting the vertical angle of the radar beam of the reflective wave; and comparing the vertical angle and the absolute speed with a predetermined angle and speed.
The electronic control unit calculates the absolute speed of the preceding vehicle as a sum of the relative speed and the vehicle speed and the predetermined angle and the predetermined speed are preferably preset to zero (0).
In the case that the vertical angle is greater than the predetermined angle and the absolute speed is different from the predetermined speed, the ECU concludes that either an incline is in front of the vehicle or the preceding object is large.
In the case that the vertical angle is greater than the predetermined angle and the absolute speed is equal to the predetermined speed, the ECU concludes that the object is stationary.
In the case that the vertical angle is less than the predetermined angle and the absolute speed is different from the predetermined speed, the ECU concludes that a decline is in front of the vehicle.